diff --git a/drivers/scsi/mac53c94.h b/drivers/scsi/mac53c94.h
new file mode 100644
index 0000000..1ad24e4
--- /dev/null
+++ b/drivers/scsi/mac53c94.h
@@ -0,0 +1,214 @@
+/*
+ * mac53c94.h: definitions for the driver for the 53c94 SCSI bus adaptor
+ * found on Power Macintosh computers, controlling the external SCSI chain.
+ *
+ * Copyright (C) 1996 Paul Mackerras.
+ */
+#ifndef _MAC53C94_H
+#define _MAC53C94_H
+
+/*
+ * Registers in the 53C94 controller.
+ */
+
+struct mac53c94_regs {
+	unsigned char	count_lo;
+	char pad0[15];
+	unsigned char	count_mid;
+	char pad1[15];
+	unsigned char	fifo;
+	char pad2[15];
+	unsigned char	command;
+	char pad3[15];
+	unsigned char	status;
+	char pad4[15];
+	unsigned char	interrupt;
+	char pad5[15];
+	unsigned char	seqstep;
+	char pad6[15];
+	unsigned char	flags;
+	char pad7[15];
+	unsigned char	config1;
+	char pad8[15];
+	unsigned char	clk_factor;
+	char pad9[15];
+	unsigned char	test;
+	char pad10[15];
+	unsigned char	config2;
+	char pad11[15];
+	unsigned char	config3;
+	char pad12[15];
+	unsigned char	config4;
+	char pad13[15];
+	unsigned char	count_hi;
+	char pad14[15];
+	unsigned char	fifo_res;
+	char pad15[15];
+};
+
+/*
+ * Alternate functions for some registers.
+ */
+#define dest_id		status
+#define sel_timeout	interrupt
+#define sync_period	seqstep
+#define sync_offset	flags
+
+/*
+ * Bits in command register.
+ */
+#define CMD_DMA_MODE	0x80
+#define CMD_MODE_MASK	0x70
+#define CMD_MODE_INIT	0x10
+#define CMD_MODE_TARG	0x20
+#define CMD_MODE_DISC	0x40
+
+#define CMD_NOP		0
+#define CMD_FLUSH	1
+#define CMD_RESET	2
+#define CMD_SCSI_RESET	3
+
+#define CMD_XFER_DATA	0x10
+#define CMD_I_COMPLETE	0x11
+#define CMD_ACCEPT_MSG	0x12
+#define CMD_XFER_PAD	0x18
+#define CMD_SET_ATN	0x1a
+#define CMD_CLR_ATN	0x1b
+
+#define CMD_SEND_MSG	0x20
+#define CMD_SEND_STATUS	0x21
+#define CMD_SEND_DATA	0x22
+#define CMD_DISC_SEQ	0x23
+#define CMD_TERMINATE	0x24
+#define CMD_T_COMPLETE	0x25
+#define CMD_DISCONNECT	0x27
+#define CMD_RECV_MSG	0x28
+#define CMD_RECV_CDB	0x29
+#define CMD_RECV_DATA	0x2a
+#define CMD_RECV_CMD	0x2b
+#define CMD_ABORT_DMA	0x04
+
+#define CMD_RESELECT	0x40
+#define CMD_SELECT	0x41
+#define CMD_SELECT_ATN	0x42
+#define CMD_SELATN_STOP	0x43
+#define CMD_ENABLE_SEL	0x44
+#define CMD_DISABLE_SEL	0x45
+#define CMD_SEL_ATN3	0x46
+#define CMD_RESEL_ATN3	0x47
+
+/*
+ * Bits in status register.
+ */
+#define STAT_IRQ	0x80
+#define STAT_ERROR	0x40
+#define STAT_PARITY	0x20
+#define STAT_TC_ZERO	0x10
+#define STAT_DONE	0x08
+#define STAT_PHASE	0x07
+#define STAT_MSG	0x04
+#define STAT_CD		0x02
+#define STAT_IO		0x01
+
+/*
+ * Bits in interrupt register.
+ */
+#define INTR_RESET	0x80	/* SCSI bus was reset */
+#define INTR_ILL_CMD	0x40	/* illegal command */
+#define INTR_DISCONNECT	0x20	/* we got disconnected */
+#define INTR_BUS_SERV	0x10	/* bus service requested */
+#define INTR_DONE	0x08	/* function completed */
+#define INTR_RESELECTED	0x04	/* we were reselected */
+#define INTR_SEL_ATN	0x02	/* we were selected, ATN asserted */
+#define INTR_SELECT	0x01	/* we were selected, ATN negated */
+
+/*
+ * Encoding for the select timeout.
+ */
+#define TIMO_VAL(x)	((x) * 5000 / 7682)
+
+/*
+ * Bits in sequence step register.
+ */
+#define SS_MASK		7
+#define SS_ARB_SEL	0	/* Selection & arbitration complete */
+#define SS_MSG_SENT	1	/* One message byte sent */
+#define SS_NOT_CMD	2	/* Not in command phase */
+#define SS_PHASE_CHG	3	/* Early phase change, cmd bytes lost */
+#define SS_DONE		4	/* Command was sent OK */
+
+/*
+ * Encoding for sync transfer period.
+ */
+#define SYNCP_MASK	0x1f
+#define SYNCP_MIN	4
+#define SYNCP_MAX	31
+
+/*
+ * Bits in flags register.
+ */
+#define FLAGS_FIFO_LEV	0x1f
+#define FLAGS_SEQ_STEP	0xe0
+
+/*
+ * Encoding for sync offset.
+ */
+#define SYNCO_MASK	0x0f
+#define SYNCO_ASS_CTRL	0x30	/* REQ/ACK assertion control */
+#define SYNCO_NEG_CTRL	0xc0	/* REQ/ACK negation control */
+
+/*
+ * Bits in config1 register.
+ */
+#define CF1_SLOW_CABLE	0x80	/* Slow cable mode */
+#define CF1_NO_RES_REP	0x40	/* Disable SCSI reset reports */
+#define CF1_PAR_TEST	0x20	/* Parity test mode enable */
+#define CF1_PAR_ENABLE	0x10	/* Enable parity checks */
+#define CF1_TEST	0x08	/* Chip tests */
+#define CF1_MY_ID	0x07	/* Controller's address on bus */
+
+/*
+ * Encoding for clk_factor register.
+ */
+#define CLKF_MASK	7
+#define CLKF_VAL(freq)	((((freq) + 4999999) / 5000000) & CLKF_MASK)
+
+/*
+ * Bits in test mode register.
+ */
+#define TEST_TARGET	1	/* target test mode */
+#define TEST_INITIATOR	2	/* initiator test mode */
+#define TEST_TRISTATE	4	/* tristate (hi-z) test mode */
+
+/*
+ * Bits in config2 register.
+ */
+#define CF2_RFB		0x80
+#define CF2_FEATURE_EN	0x40	/* enable features / phase latch */
+#define CF2_BYTECTRL	0x20
+#define CF2_DREQ_HIZ	0x10
+#define CF2_SCSI2	0x08
+#define CF2_PAR_ABORT	0x04	/* bad parity target abort */
+#define CF2_REG_PARERR	0x02	/* register parity error */
+#define CF2_DMA_PARERR	0x01	/* DMA parity error */
+
+/*
+ * Bits in the config3 register.
+ */
+#define CF3_ID_MSG_CHK	0x80
+#define CF3_3B_MSGS	0x40
+#define CF3_CDB10	0x20
+#define CF3_FASTSCSI	0x10	/* enable fast SCSI support */
+#define CF3_FASTCLOCK	0x08
+#define CF3_SAVERESID	0x04
+#define CF3_ALT_DMA	0x02
+#define CF3_THRESH_8	0x01
+
+/*
+ * Bits in the config4 register.
+ */
+#define CF4_EAN		0x04
+#define CF4_TEST	0x02
+#define CF4_BBTE	0x01
+
+#endif /* _MAC53C94_H */